Malodors are offensive odors, which are encountered in the air and on many substrates such as fabrics, hard surfaces, skin, and hair. Amines, thiols, sulfides, short chain aliphatic and olefinic acids, e.g., fatty acids, are typical of the chemicals found in and contributed to sweat, household, and environmental malodors. These types of malodors typically include indole, skatole, and methanethiol found in toilet and animal odors; piperidine and morpholine found in urine; pyridine and triethyl amine found in kitchen and garbage odors; and short chain fatty acids, such as 3-methyl-3-hydroxyhexanoic acid, 3-methylhexanoic acid or 3-methyl-2-hexenoic acid, found in axilla malodors. Compounds which have been found in the axilla are described for example by Zeng, et al. ((1991) J. Chem. Ecol. 17:1469-1492).
Malodor counteractants or masking agents have been described in the art. For example, sulfhydryl reactants, such as diethyl fumarate, di-n-butyl maleate and N-ethylmaleimide are disclosed in U.S. Pat. No. 5,601,809 as compounds that are effective against axillary malodor. Further, the use of certain aromatic unsaturated carboxylic acid esters in combination with alkyl fumarates as malodor counteractants is disclosed in U.S. Pat. No. 6,610,648. U.S. Pat. No. 6,403,075 addresses fragrance materials with a phenyl ring moiety as ammonia masking agents. Similarly, US 2002/0058017 describes cis-3-hexenol to mask ammonia. Moreover, U.S. Pat. No. 7,585,833 describes methods for formulating fragrances to mask malodor present in products containing ammonia and substituted amines (U.S. Pat. No. 6,379,658, U.S. Pat. No. 6,376,741, U.S. Pat. No. 5,769,832, and U.S. Pat. No. 5,037,412).
Although the art describes compositions and methods for neutralizing certain malodors, there still remains a need for additional compounds that are more efficient against malodors and have a relatively low impact on the olfactive character of a fragrance.